Control circuit



May 16, 1939. w. A. RAY 2,158,706: i

v '1 CONTROL CIRCUIT Filed Aug. 9, 1937 J POWER LOAD P WE

25' W 26 l6 l5 7 INVENTOR,

WILLIAM A. RAY. I BY M ATTORNEY Patented May 16, 1939 CONTROL CIRCUIT .William A. Ray, Glendale, Calif.

. 6 Claims.

My invention relates to electrical control circults and has for its chief object the provision of. an improved circuit whereby electric devices may be applied to influence circuit-opening-andclosing controlapparatus connecting a source of electrical power, without the requirement of additional power supply wires for said electric devices.

A particular object of my invention is the provision or an improved electrical circuit for connecting an electrlc-motor-operated time-delay device designed to influence circuit-openingand-closing apparatus for controlling physical conditions, such as temperature, humidity, etc., without the requirement or power supply wiring in addition to that leaifing to said control ap-,

paratus.

Other objects and advantages will be apparent during the course of the following description.

I Referring to the drawing:

Figure 1 is a diagrammatic view showing my invention applied to a conventional 2-wire thermostat circuit; and a Figure 2 is a similar. view showing my invention applied to a conventional 3-wire,therm0- stat circuit.

Referring more particularly to Fig. l of the drawing, the numeral ll denotes a thermostatic element of conventional bi-metal construction carrying the contact i2 and capable of movement on decrease of temperature to cause coaction between said contact I2 and the fixed contact snap-action (not shown), having a moving arm I5 designed to coact with either of the fixed contacts l6--l| and having manual operating means, as by the knob l8. l9 denotes an electric motor having a driven shaft 20 to which is adjustably attached the operating arm 2| as bythe thumb screw 22 and designed to cooperate with the extension arm 23 of the switch I4". The

manually operable cam 24 is adapted to hold the arm I5 away from the .contact l6 to open the circuit for purposes that will be explained later. Extended, as shown by the broken lines, are the designated connections for a source of electrical power and a load.

Referring now to Fig. 2 of the drawing, the numeral 25 denotes a bi-metallic thermostatic element carrying a contact 26 and capable of movement on decrease of temperature to cause coaction between said contact 26 and -the fixed.

contact 21. Attached to the element 25 is a flexible extension 28 carrying a contact 29 engageable with the fixed contact 30. The switch IS. A switch It, preferably having Application August 9, 193?,Serial No. 158,126

l4 and the motor [9 and their associated parts are identical with those shown in Fig. 1. Extended, as shown by the broken lines, are the designated connections for a source of electrical power and a load, in the form of a relay 3| hav- 5 ing a winding 32, a core 33 and an armature 34 engageable with the fixed contact 35. Arranged to move with the armature 34, but insulated therefrom, is another armature 36 engageable' with the fixed contact3'l, affording means for 10 switching power to a load devi'ce.

Referring again to Fig. 1, it will be seen that the thermostat is connected through the switch arm I! when it is in the on position to complete the power circuit to the load. On decrease 16 of temperature, the .thermostat contacts l2l3 close and the load is energized. The said load may be an electrically operated gas valve for a heating system, motor furnace operator, or sim: ilar device. the heating system during the night so the switch is turned to the oil position, rendering the thermostat contacts inoperative to complete the circuit to the load.

In this position of the switch the power cir- 25 cuit to the-motor I9 is complete through the off contact, the switch arm and the load device. The impedance of the motor may be high in relation to that of the load, so sufiici'ent power is passed through the load to operate the motor. 30 But, for the same reason, insufllcient power is passed through the motor to operate the load device. a

The timingarm 2| of the motor is arranged to make one complete revolution in, say, 12 hours. 5 So any time delay less than 12 hours may be arranged as desired by adiusting the starting position of the timing arm 2| so that it will travel through some certain fraction of a revolution before it strikes the extension arm 23 to turn 4 on" the switch H, when the heating system will be put into operation if the thermostat contacts are closed responsive to low temperature. At the same time the power circuit to the motor is opened. The switch It may preferably be of 45 the snap-action type so that there is no appreciable time lapse in operating it between its on and off positions and so that the motor circuit will not be opened before the switch has completed its movement. The motor may prefer- 50 ably be of the synchronous-speed alternating indefinite length of time, the motor circuit 55 It is usually undesirable to operate 30,

through the "ofi position of the switch may be opened, as by rotating the cam 24 to hold the arm l5 away from the contact l6.

In Fig. 2 a different type of thermostat is shown, having a flexible contact-carrying extension arm 28 attached to and movable with the bi-metallic member 25 and arranged so that, on movement of the thermostat in response to decrease in temperature, circuit is first made through contacts 29 and before it is made through the contacts 26 and 21. Likewise, on reverse movement of the thermostat, contacts 26 and 21 separate before contacts 29 and 30. In operation, presuming the switch H to be on, when the contacts 25-30 close, no other action takes place. But when the thermostat moves further and closes contacts 26-21 in addition, the power may then flow from contact I! through switch-arm l5, contacts 30-49, members 28 and 25, contacts 26-21 to complete the circuit through the relay winding 32. When thus energized, the armature 34 is attracted'to complete its circuit through contact 35 which provides a holding circuit for the relay so that, on decrease of temperature, the relay does not become de-energized until the circuit is finally opened on separation of the contacts 29-40. The thermostat circuit shown in Fig. 2 is a conventional 3-wire control circuit designed to provide a definite time lag between the energizing and de-energizing of the relay and no claim is made to it by me. My invention has been shown applied to the thermostat circuit by means of the switch M, the motor l9 and their associated parts and the operation is similar to that described in reference to Fig. l, the only difference being that in Fig. 2 the load, through which the circuit for the motor is completed, is definitely shown as a relay winding. The small amount of current passed by the motor through the relay winding is not suflicient to operate the relay. And likewise, the impedance of the relay winding, being low in respect to that of the motor, permits sufficient current to pass to operate the motor.

It will be seen that I have provided a control circuit that permits the addition of an electricmotor-operated timer to a thermostat circuit without the requirement of wiring in addition to that necessary for the thermostat control operation minus such a device. This is an important matter, as the controlled apparatus is usually far from the thermostat or thermostats and the running of one or two additional wires to each control position involves a considerable installation expense and possibility of misconnections. By my invention, a self-contained unit including a thermostat and an electric timer therefor may be installed as simply as a thermostat alone.

While I have shown my invention applied to conventional thermostat circuits, it will be readily understood that it may be in similar ways applied to other systems for controlling physical conditions, in which a circuit is opened and closed in response to variation in said conditions.

The particular apparatus shown is merely illustrative and modifications may be made therein.

I desire it to be understood that no limitation on the invention is intended than is imposed by the scope of the appended claims.

I claim as my invention: 1. In a control system, a first electric circuit including in series a. source of power, a load, a switch comprising a member movable into alternative contact positions, and means responsive to change in physical conditions to control said load;

an electric time-delay device adapted to move said member into position to close said first circuit after a predetermined lapse of time; and a second electric circuit including in series said time-delay device, said load, said source or power, and said switch; said switch being adapted, in one position of said member, to close said first circuit and simultaneously to open said second circuit and, in the alternative position of said member, to open said first circuit and simultaneously to close said second circuit.

2. In a control system, a first electric circuit including in series a source of power, a load, a switch comprising a member movable into alternative contact positions, and means responsive to change in physical conditions to control said load; an electric time-delay device adapted to move said member into position to close said first circuit after a predetermined lapse of time; and a second electric circuit including in series said time-delay device, said load, said source of power, and said switch; said switch being adapted, in one position of said member, to close said first circuit and simultaneously to open said second circuit and, in the alternative position of said member, to open said first circuit and simultaneously to close said second circuit; said electric time-delay device having high impedance in respect to that of said load whereby insufficient power is passed by said device to operate said load.

3. In a control system, a first electric circuit including in series a source of power, a load, a switch comprising a member movable into alternative contact positions, and a thermostat to control said load; an electric time-delay device adapted to move said member into position to close said first circuit after a predetermined lapse of time; and a second electric circuit including in series said time-delay device, said load, said source of power, and said switch; said switch being adapted, in one position of said member, to close said first circuit and simultaneously to open said second circuit and, in the alternative position of said member, to open said first circuit and simultaneously to close said second circuit.

4. In a control system, a first electric circuit including in series a source of power, a load, a switch comprising a member movable into alternative contact positions, and a thermostat to control said load; an electric time-delay device adapted to move said member into position to close said first circuit after a predetermined lapse of time; and a second electric circuit including in series said time-delay device, said load, said source of power, and said switch; said switch being adapted, in one position of said member, to close said first circuit and simultaneously to open said second circuit and, in the alternative position of said member, to open said first circuit and simultaneously to close said second circuit; said electricv time-delay device having high impedance in respect to that of said load whereby insufficient power is passed by said device to operate said load.

5. In a control system, a first electric circuit including in series a source of power, a load, a switch comprising a member movable into alternative contact positions, and a thermostat to control said load; a synchronous electric-motoroperated time-delay device adapted to move said member into position to close said first circuit after a predetermined lapse of time; and a second electric circuit including in series said timedelay device, said load, said source of power, and

said switch; said switch being adapted. mane position as said member, to close said first circuit and simultaneously to open said second circuit and, in the alternative position 0! said member,

that of said load whereby insufiicient power is passed by said device to operate said load.

10 6. In a control system, a first electric circuit including'in series a source of power, a load, a switch comprising a member movable into alternative contact positions, and a thermostat to control said load; anelectric time-delay device adapted to move said member into position to close said first circuit after a predetermined lapse of time; a second electric circuit including in series said time-delay device, said load, said source of power, and said switch; said switch being adapted. in one position of said member, to close said first circuit and simultaneously to open said second circuit and, in the alternative position of said member, to open said first circuit and simultaneously to close said second circuit; and means for temporarily rendering said switch member inoperable to close said second circuit.

WILLIAM A. RAY. 

